i ONed debug mode and enter into carbuilding mode - i get big CROSS, up and left rays is green and down and right rais is red.
pardon, is i right undersand, what i need to build car exactly AROUND “begin point” of car??? (other name PIVOT)
and - AFAI understood - i need to CMPLETELLY disassemble my car 
and - is car may have boom cranes for lifting himself for [dis]mounting wheels?
one boom for frontside and one boom for rear side.
no? only i need to build boom-cart?